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19.4.2005. TUT: 83180 Wireless LANs. 2. Outline. Introduction802.11k measurementsHow it worksConclusions Current status of 802.11kReferences. 19.4.2005. TUT: 83180 Wireless LANs. 3. Introduction. Task group k launched in late 2002Define radio resource measurement (RRM) parameters for network m
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1. 19.4.2005 TUT: 83180 Wireless LANs 1 802.11k Radio Resource Measurements
Kai Törmä
2. 19.4.2005 TUT: 83180 Wireless LANs 2 Outline Introduction
802.11k measurements
How it works
Conclusions
Current status of 802.11k
References
3. 19.4.2005 TUT: 83180 Wireless LANs 3 Introduction Task group k launched in late 2002
Define radio resource measurement (RRM) parameters for network management and performance enhancement
provide mechanisms to higher layers for radio and network measurements
4. 19.4.2005 TUT: 83180 Wireless LANs 4 802.11k Measurements Make measurements from layer 1 and 2 of OSI protocol stack
Statical Measurement
Characterize the radio environment in long-term statistical sense
Identity Measurements
Identify stations that affect each other’s performance
5. 19.4.2005 TUT: 83180 Wireless LANs 5 802.11k measurements Channel Load
Noise
Histogram
Beacon Frame
Hidden Node
Medium Sensing
Time Histogram
STA Statistics
Transmit power control (802.11h) These are addition to the power measurements that were defined in 802.11h.These are addition to the power measurements that were defined in 802.11h.
6. 19.4.2005 TUT: 83180 Wireless LANs 6 Roaming decision APs can provide a site report to clients
APs collects data with beacon frames and will analyse it
AP generates an ordered list of access points, from best to worst service, called a site report AP asks with beacon request a client repots all the access point beacons it hears.AP asks with beacon request a client repots all the access point beacons it hears.
7. 19.4.2005 TUT: 83180 Wireless LANs 7 Channel selection Currently APs and clients cannot share channel information
With 802.11k
Noise histogram
Channel load
Time histogram
-> AP will know is the channel quality good enough
8. 19.4.2005 TUT: 83180 Wireless LANs 8 Hidden nodes Clients or APs that other clients or access points can’t hear
With 802.11k
Clients track hidden nodes and access points query clients with those lists
APs knows now about clients who are on the edge of their cells
9. 19.4.2005 TUT: 83180 Wireless LANs 9 Client statistics Currently are limited to statistics APs maintain
With 802.11k
802.11 MAC statistics
Counts of MSDUs/MPDUs received/transmitted
Counts of Channel utilization in rx & tx direction
Data rate & modulation of last rx and tx
RSSI, RCPI, and signal quality
Etc.
-> More complete view of network performance
10. 19.4.2005 TUT: 83180 Wireless LANs 10 How it works Client is moving away AP1, so AP1 informs the client prepare to move to another access point
The Client asks the AP1 to provide it with a list of preferred access points nearby
AP1 responds with a site report
Client moves to the channel of best access point listed in the site report and connects it
11. 19.4.2005 TUT: 83180 Wireless LANs 11 Benefits Simplify WLAN radio configuration
Enable better diagnostics of problems
Using info that is easy and cheap to gather
Enable new services
Location based services
Voice Over IP (VOIP)
Enable better frequency planning, optimize network performance
Enable automatic frequency planning
Better traffic distribution
12. 19.4.2005 TUT: 83180 Wireless LANs 12 Changes to STAs Wireless MAC message protocol
Build upon 802.11h mechanisms and measure frames
add RRM capability bit and RRM action frame type
MAC firware
Handle new management frames in the wireless MAC protocol
Compute measurement payloads form PHY registers and traffic
13. 19.4.2005 TUT: 83180 Wireless LANs 13 Conclusions Better wireless performance and management
Better Observation of Access point
Better Client performance
Take Environmental data into consideration
14. 19.4.2005 TUT: 83180 Wireless LANs 14 Conclusions Measurements necessary for future wireless growth
Future technologies require more measurement
Once ratified, 802.11k would help IT build a better WLAN
15. 19.4.2005 TUT: 83180 Wireless LANs 15 802.11k status Mar 05 2nd Letter Ballot in Progress Currently
Expect to go to Sponsor Ballot Summer or Fall 05
Expect to be a standard by the end of 05 or early 06
16. 19.4.2005 TUT: 83180 Wireless LANs 16 References Radio resource measurements (11k) intro IEE 802.11-05/0184r0 [ftp://ieee:wireless@ftp.802wirelessworld.com/11/05/11-05-0184-00-000k-radio-resource-measurement-11k-intro.ppt]
Technical article: Demystifying IEEE 802.11 for industrial wireless lans [http://wireless.industrial-networking.com/articles/articledisplay.asp?id=225]
Searchmobilecomputer.com 802.11k [http://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci999671,00.html]
802.11k makes WLANs measure up [http://www.nwfusion.com/news/tech/2004/0329techupdate.html]
Which 802.11 standards will actually make a difference? [http://www.techworld.com/mobility/features/index.cfm?fuseaction=displayfeatures&featureid=1065&page=1&pagepos=1]
Developements of IEEE 802.11 technology [http://www.electronics.dit.ie/staff/mdavis/EI_talk_summary.pdf]
An adaptive approach to wireless network performance optimization [http://www.intel.com/technology/magazine/communications/wi02043.pdf]